1 of 29

ME610: Final Presentation

​

Design and Analysis of HVAC system for Apple Campus

Arvind Balasubramani, Nha Uyen Huynh, Arisara Im-Aurb, Surabhi Nimbalkar, Prathemesh Modi

Date: 04/27/2016

San Diego State University

2 of 29

A design by Norman Foster

Adjustable Louvers

Apple Campus

3 of 29

Source: fastcodesign.com

According to statement of Lisa Jackson (Apple's vice president of environmental),

​

  • No net increase in greenhouse gas emissions
  • 80% of the site is green space
  • 75% of the year won't need air conditioning -> Natural ventilation

Introduction - Problem Definition

4 of 29

Source: http://contentwithpictures.com/

Adjustable Louvers

Proposed HVAC system

5 of 29

Floor Plan

5

3

2

4

1

Cafeteria

Work space

Source: http://st.pixanews.com/

  • 4 storied structure.
  • Materials used: Walls: Glass
  • Ceilings and Floor: Concrete
  • Inner radius: 521 Feet
  • Outer Radius:813 Feet
  • Estimated Employees: 13000

​

​

6 of 29

Natural Ventilation

  • Airflow through an indoor space without a mechanical system.

​

  • Increase thermal comfort ability and efficiency

​

  • Traditional → Windows

​

  • Apple HQ design

7 of 29

Natural Ventilation

Mixed Ventilation

Stack-Driven Ventilation

A

B

Figure: (A) Air flow pathway of mixed ventilation, (B) Air flow pathway of stack-driven ventilation [5]

8 of 29

Standards: ASHRAE 62.1 & ASHRAE 55

Source: https://www.ashrae.org/

Figure: ASHRAE 62.1 Standard

Figure: ASHRAE 55 Standard

9 of 29

Design by Rule Procedure

Design Condition

Minimum Required Flow Rate, ASHRAE 62.1

Minimum Required Velocity

Adjust Velocity to reduce temperature, ASHRAE 55

Used in COMSOL

Cupertino, 88 ºF in Summer

Required airflow rate (CFM or m^3/s)

Required velocity (fps or m/s)

10 of 29

Required Airflow Rate Calculation (ASHRAE62.1)

​

​

  1. Breathing Zone Outdoor Airflow:

​

​

​

  • Zone Air Distribution Effectiveness (EZ)
    • Determined from Table 6.2
    • For Ceiling supply of cool air -> EZ = 1

​

  • Zone Outdoor Airflow:

​

Ventilation Rate Procedure (Zone Calculation):

People

Area

11 of 29

Table 6.1: Max. Ventilation Rate in Breathing Zone

​

  • Cafeteria/fast food dining
    • RP = 9 cfm/person
    • RA = 0.18 cfm/ft^2
    • Occupant density: 100 person/1000ft^2

​

  • Office space
    • RP = 17 cfm/person
    • RA = 0.06 cfm/ft^2
    • Occupant density: 5 person/1000ft^2

​

​

Source: https://www.ashrae.org/

Required Airflow Rate Calculation (ASHRAE62.1)

12 of 29

Design by Rule: Results

Results:

13 of 29

- Indoor temperature (summer) = 88ºF – 4.6ºF = 83.4 ºF

- Air Velocity = 0.8 m/s - - > Used in COMSOL

Source: http://sustainabilityworkshop.autodesk.com/

Required Air Velocity (ASHRAE 55)

14 of 29

Design 1.0

Design Dimensions:

1.Diameter = 0.8 m

2. Blades length = 0.204 (~30°)

3. Separator height = 0.25 m

15 of 29

Design 1.0

​

​

Mesh Statistics:

1. Number of mesh elements = 3513

2. Number of degrees solved for = 14209

3. Mesh Type: Boundary Mesh

16 of 29

Design 1.1

17 of 29

Design 1.1

Particle Tracing

18 of 29

Design 1.2

Mesh Statistics:

​

# of meshed elements = 6396�# of degrees of freedom solved for = 22585�

19 of 29

Design 1.3

Mesh Statistics:

# of meshed elements = 328

# of degrees of freedom solved for = 2411

Inlet

Outlet

20 of 29

Boundary Conditions:

  1. Inlet Pressure = 1e5Pa
  2. Outlet velocity = 0.8 m/s
  3. Other boundaries = Wall/ No slip

21 of 29

Boundary Conditions:

  • Inlet Pressure = 1e5 Pa
  • Outlet velocity = 1.6 m/s
  • Other boundaries = Wall/ No slip

22 of 29

Ventilation

(Demo model)

Dimensions:

Room: 2mx3m

​

Mesh size: 6304

Number of degrees solved for: 42053

​

Inlet Pressure = 1e5 Pa

Oulet Velocity = 3 m/s

Inlet

Outlet

23 of 29

Inlet Pressure = 1e5 Pa

Oulet Velocity = 3 m/s

Horizontal Velocity field distribution

Vertical Velocity field distribution1

Vertical Velocity field distribution2

1

2

24 of 29

Ventilation

Actual building room with Air duct system on both sides.

25 of 29

Dimensions:

Width of room = 88 m

Height of room = 3 m

​

Boundary Conditions :

Inlet Pressure = 1E5 Pa

Outlet velocity = 1m/s

​

Max Velocity= 11.46 m/s

​

26 of 29

Velocity distribution with 0.8 m/s as max value.

​

​

27 of 29

Velocity distribution at different cross section moving away from the duct to the center.

Velocity distribution across the whole room

28 of 29

Conclusion

  1. For the current room size, the designed air duct system is not sufficient for natural ventilation to occur.
  2. Forced ventilation or multiple exhausts are required

​

Future Scope:

​

  1. Size of the air duct system should be increased
  2. Multiple air duct systems can be designed to ventilate the entire area of the room
  3. Optimization of blade design
  4. Actuating system for adjusting louvers
  5. Repositioning of Inlet/outlet for natural ventilation

​

29 of 29

References

[1]Ashrae Standard 55, [website], 2016, https://www.ashrae.org/resources- -publications/bookstore/standard-55, (accessed 25 March 2016). 

​

[2]Natural Ventilation, [website] ,2016, http://sustainabilityworkshop .autodesk.com/buildings/natural-ventilation, (accessed 16 April 2016). 

​

[3]California Design Location Data , [website],2011, http://www.energy.ca.gov/title24/archive/2001standards/nonresidential_manual/13_Appendix_C.pdf, (accessed 16 April 2016). 

​

[4]Ashrae Standard 62.1, [website], 2016, https://ashrae.iwrapper.com/ViewOnline/Standard_62.1-2013, (accessed 18 March 2016). 

​

[5]Linden, Paul F. "The fluid mechanics of natural ventilation." Annual review of fluid mechanics 31.1 (1999): 201-238.

​

Acknowledgements: Dr. Sam Kassegne